Constricted blood flow in human arteries due to build-up of plaque is a common ailment and creates serious risks to the quality of life and, in some cases, e.g., when build-up occurs in coronary arteries, to life itself, too frequently at an early age.
Past efforts to address the problem of plaque accumulation in arteries have consisted primarily of conventional endarterectomy, by-pass surgery, dilation of the afflicted arteries using dottering or balloon angioplasty (PTA and PTCA), atherectomy, and successive severing of thin layers of plaque by reason of repeated passes of a cutting or grinding instrument along the plaque region where removal is desired. The plaque-cutting technique also requires that debris, in the form of plaque fragments released into the blood stream, be collected and removed from the artery to avoid complications (such as embolization and thrombosis). Laser removal of plaque is also known.
Conventional endarterectomy is invasive. By-pass surgery is traumatic to the tissue, very expensive, very invasive, and creates the greatest risk to the patient. Balloon angioplasty and/or dottering are often only a temporary or short-term solution, as all of the plaque in the afflicted artery at the time of treatment remains there. Dilation only rearranges plaque and may cause pieces of plaque to break loose into the blood stream. Additional build-up of plaque at the site of treatment can be prevented or alleviated by exercise and diet control, if patient compliance can be achieved. Atherectomy has demonstrated poor long-term results, at least in peripheral vessels.
Repeated cutting of the atheroma using a reciprocated instrument offers promise, but cannot be performed rapidly, may not remove all of the plaque at the treatment site, and risks complications when and if plaque fragments are not collected and thus escape to flow with blood to other parts of the cardiovascular system. Laser removal of plaque has also shown poor long-term results in some studies.
All present treatments exhibit restenosis, a complex, poorly understood process by which the artery becomes re-blocked by material that includes uncontrolled growth of smooth muscle cells (intimal hyperplasia or myointimal fibroplasia). All present treatments vary in peri-operative measures of desirability, including duration of procedure, degree of invasiveness of procedure, number and size/length of surgical incisions required, length of stay in hospital, recuperation/healing time, time until return to work, degree of anesthesia (local/general) required, overall procedure risk, and overall treatment cost.